ASTM C756-87(2011)e1
(Test Method)Standard Test Method for Cleanability of Surface Finishes
Standard Test Method for Cleanability of Surface Finishes
SIGNIFICANCE AND USE
This test method was developed to guide the user in selecting a finish coating or material that is resistant to soiling in a particular application.
The numerical values derived by this test method enables the user to rank finish coatings and materials in regard to soil retention or ease of soil removal.
SCOPE
1.1 This test method covers the numerical evaluation of the ease or difficulty of cleaning soiled surface finishes. This test method is applicable to all surface finishes not affected by water.
1.2 Values given in SI units are to be regarded as the standard. Inch-pound units are provided for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation: C756 − 87 (Reapproved 2011)
Standard Test Method for
Cleanability of Surface Finishes
This standard is issued under the fixed designation C756; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Test Method was corrected editorially in 2011
INTRODUCTION
This test provides a procedure to quantify the cleanability of acid-resistant porcelain enamel using
a fluorescent water-soluble soil in agent, a reproducible machine-wiping technique, and a means of
measuring the amount of residual soil by fluorescence.
1. Scope the solution measured. A standard reference surface is treated
inasimilarmanner.Thecleanabilityindexofthesurfaceunder
1.1 This test method covers the numerical evaluation of the
testisexpressedastheratioofthefluorescenceofthesolutions
ease or difficulty of cleaning soiled surface finishes. This test
extracted from the test surface and from the standard reference
method is applicable to all surface finishes not affected by
surface. Cleanability indexes greater than 1.0 indicate that the
water.
test surface is more difficult to clean than the standard
1.2 Values given in SI units are to be regarded as the
reference surface, while indexes less than 1.0 indicate that the
standard. Inch-pound units are provided for information only.
test surface is more easily cleanable than the standard of
1.3 This standard does not purport to address all of the
comparison.
safety concerns, if any, associated with its use. It is the
3.2 The soiling agent used consists of polyethylene glycol,
responsibility of the user of this standard to establish appro-
a black dye, and a fluorescent tracer, each of which is readily
priate safety and health practices and determine the applica-
water soluble.
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
4.1 This test method was developed to guide the user in
2.1 ASTM Standards:
selecting a finish coating or material that is resistant to soiling
C282 Test Method for Acid Resistance of Porcelain Enam-
in a particular application.
els(Citric Acid Spot Test)
4.2 The numerical values derived by this test method
C614 Test Method forAlkali Resistance of Porcelain Enam-
enables the user to rank finish coatings and materials in regard
els
to soil retention or ease of soil removal.
3. Summary of Test Method
5. Apparatus
3.1 The test method consists of applying an exact amount of
a fluorescent water-soluble soiling agent to a specimen surface 5.1 Motor-Driven Lapping Plate, 203-mm (8-in.) diameter,
and then cleaning the surface with a reproducible machine- speed 163 r/min.
wiping technique. The soil remaining on the specimen after
5.2 Automatic Polishing Unit, 11-s cycle, adjustable to
wipingisextractedwithawatersolventandthefluorescenceof 4
48-mm (1 ⁄8-in.) stroke.
5.3 Hypodermic Syringe, glass, 2-mL capacity, without
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic
needle.
and Inorganic Coatingsand is the direct responsibility of Subcommittee B08.12 on
Materials for Porcelain Enamel and Ceramic-Metal Systems.
Current edition approved April 1, 2011. Published April 2011. Originally
approved in 1973. Last previous edition approved in 2006 as C756 – 87 (2006). Suitable lapping plates are available from Buehler Ltd., 2120 Greenwood St.,
DOI: 10.1520/C0756-87R11E01. Evanston, IL60204, Struers, Inc., 20102 Progress Drive, Cleveland, OH, 44136; or
For referenced ASTM standards, visit the ASTM website, www.astm.org, or other Metallurgical Supply Sources.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM An Olsen “S.M.” Automatic Polisher has been found suitable and is available
Standards volume information, refer to the standard’s Document Summary page on under the code name OLPOL from Struers, Inc., 20102 Progress Drive, Cleveland,
the ASTM website. OH 44136.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C756 − 87 (2011)
5.4 Repeating Pipet, 0.025 mL (25 µl) capacity. 6. Reagents and Materials
5.5 Repeating Pipet, 10-mL capacity. 6.1 Cleaning Tissues, approximately 127 by 229 mm (5 by
9 in.).
5.6 Desiccator approximately 254 mm (10 in.) diameter.
6.2 Potassium Carbonate.
5.7 Cleaning Head, brass, 57 mm (2 ⁄4 in.), with worm-
driven hose clamp for attachment of cleaning tissues (Fig. 1). 6.3 Polyethylene Glycol, 400.
Cleaning Head, Brass Soiling Head, Brass
Metric Equivalents
AB C D E F G H
1 5 7 3 5 3 3
in. 2 ⁄4 ⁄8 ⁄8 ⁄16 1 ⁄8 ⁄4 ⁄16
(mm) (57) (16) (22) (5) (25) (16) (19) (5)
FIG. 1 Cleaning and Soiling Heads
5.8 Soiling Head, brass, 25 mm (1 in.) diameter, with 6.4 Uranine, water-soluble, USP.
25-mm (1-in.) diameter facing of polytetrafluoroethylene at- 9
6.5 Keco Acid Black, B(F101).
tached with a water-proof household cement (Fig. 1).
6.6 Ethyl Alcohol.
5.9 Extraction Cell, fitted with a fluorosilicone O-ring, size
5 6.7 Mild Household Detergent, liquid.
1 1
3.2 by 57 mm ( ⁄8 by 2 ⁄4 in.) (Fig. 2).
5.10 Fluorometer, for measuring the fluorescence of solu-
7. Test Specimens
tions.
7.1 The preferred specimen size is 114 mm (4 ⁄2 in.) square,
5.11 0.9NeutralDensityFilter,50.8by50.8mm(2by2in.)
but any other size or shape may be used provided it can be
glass mounted (transmission 12.5 %).
rotated on the lapping wheel and the smaller dimension is
between 102 and 127 mm (4 and 5 in.). Sharp or jagged edges
5.12 Beakers, borosilicate, 100-mL capacity.
shall be filed or honed to prevent snagging of the cleaning
tissues during the mechanical cleaning process.
O-rings must be fluorosilicone polymer; consult Precision Associates, 742 N.
Washington Ave., Minneapolis, MN 55401; Parker Seal Co., 10567 W. Jefferson
7.2 Twelvespecimensarerequiredtoevaluatethecleanabil-
Blvd., Culver City, CA 90230; & B. W. Rogers (Parker Dis.) 1000 Brookpark Rd.,
ity index, that is, six of the candidate surface, and six of a
Cleveland, OH 44109. Also see other sources in Thomas Register under SEALS:
“O” RINGS.Asuitable device for clamping the cell to a specimen is shown in Fig.
3 and Fig. 5.
Turner Fluorometer, Model 111 (Turner 111-003) available from Curtin Cel-Fibe Wipes, Type 1745 or equivalent.
Matheson Scientific, Inc., 10727 Tucker St., Beltsville, MD 20705, Sequoia-Turner Uranine is the sodium salt of fluorescein, C H O Na .
20 10 5 2
Dial Model 111, Fisher Scientific Co., 711 Forbes Ave., Pittsburg, PA 15219, and Awater-soluble fabric dye used principally for nylon, silk, and wool; available
other principal cities for both. from Keystone Aniline and Chemical Co., 321 N. Loomis, Chicago, IL 60607.
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C756 − 87 (2011)
Metric Equivalents
AB C D E F G H I
1 1 1 1 1 5 1 7 1
in. ⁄16 ⁄8 ⁄64 2 ⁄2 1 ⁄4 ⁄8 ⁄16 1 ⁄8 2 ⁄8
(mm.) (1.6) (3.2) (0.4) (64) (32) (16) (1.6) (47) (54)
All surfaces to be plated with bright nickel.
FIG. 2 Brass Extraction Cell
porcelain enamel standard reference surface for cleanability. shall be added last and thoroughly mixed in the blender. This
Porcelain enamel specimens are not damaged by the cleanabil- soiling agent shall be stored in a tightly stoppered glass bottle
ity test and may be cleaned and reused many times. Specimens at least overnight before use.
have been reused as many as 50 times without damage or solid
9. Procedure
buildup.
9.1 Specimen Pretreatment—Scrub the specimens with a
NOTE 1—The porcelain enamel covercoat used to coat the standard
cellulose sponge wet with a 1 % solution of a mild household
reference surface shall have the following characteristics: Acid Resis-
tance:AA(Test Method C282)Alkali Resistance: Maximum 1.55 mg/cm detergent at room temperature. Rinse in turn with tap water,
wt. loss (Test Method C614).
distilled water, and ethyl alcohol, and allow to dry in a
near-vertical position at room temperature. Store the washed
8. Preparation of Standard Soil
and dried specimens overnight in a desiccator charged with a
8.1 The soiling agent shall consist of the following:
saturated solution of potassium carbonate.
Ingredient Weight %
9.2 Conditioning of Cleaning Tissues—Cut a supply of
Polyethylene glycol 98
tissues ample for use in specimen cleaning treatment in the
Keco Acid Black B 1
Uranine, water-soluble 1
following paragraph into approximately 102-mm (4-in.)
8.2 The uranine shall be added to the polyethylene glycol in squares and store overnight, before use, in a desiccator charged
food blender and mixed by alternate periods of mixing and with a saturated solution of potassium carbonate (relative
standing until the crystalline uranine appears to be completely humidity approximately 45 %). Allow the tissues to remain in
dissolved in the glycol. The black dye which obscures all else the desiccator until just prior to use.
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C756 − 87 (2011)
Metric Equivalents
AB C D E F G H I J K L M N
1 1 3 1 7 5 1 1 1 5 5
in. ⁄16 2 ⁄4 1 ⁄8 ⁄4 1 ⁄8 ⁄16 56 1 ⁄4 3 ⁄4 ⁄4 4 ⁄8 4 ⁄8 5
(mm) (1.6) (64) (35) (6.4) (47) (8) (127) (152) (32) (83) (6.4) (117) (117) (127)
FIG. 3 Device for Clamping Extraction Cell to Specimen
9.3 Soiling and Cleaning Treatments: 22 s (so that it will stop as well as start at the center of the
9.3.1 Lay out six specimens face up on a table. Homogenize specimen). Remove the cleaning head without sliding motion.
thesoilingagentbyup-endingseveraltimesbeforeuse.Fillthe
Repeat the cleaning operation with the second tissue-covered
hypodermic syringe with no needle attached with the soiling head,usingthesameamountofdistilledwaterandforthesame
agent by withdrawing the plunger. Expel this charge of soil
22-s period.
back into the soil bottle. Then fill the syringe again. Wipe the
9.3.3 Store the first soiled and cleaned specimen in a near
tipofthesyringewithacleaningtissueandexpelseveraldrops
vertical position in a rack while applying exactly the same
into the soil bottle. Then, without rewiping the tip, hold the
series of soiling and cleaning treatments to the five remaining
syringe vertically over a specimen and discharge one drop near
specimens.
the center of each of the six specimens. Center the first
9.4 Water Extraction of the Soil Retained—Remove the
specimen on the lapping wheel and hold it in place by means
small, often nonvisible, amounts of soil from the central
of adhesive tape across the specimen corners. Place the
portion of the soiled and cleaned specimens with 10 mL of
polytetrafluoroethylene-faced soiling head on the soil, and
distilled water in the O-ring sealed extraction cell by the
engage the spindle (Fig. 4) of the polishing unit. Operate the
following sequence of operations within 30 min after soiling;
lapping wheel and the polishing unit for 1 min to distribute the
place the first soiled and cleaned specimen, face up, in the
soil over the central portion of the specimen (Fig. 5). Remove
center of the cell clamping frame. Place a clean and dry
the soiling head and clean it with tissue for reuse. Adjust the
spindle so that it rests over the center of the soil spot. Prepare extraction cell (Fig. 2) on the center of the specimen so that the
O-ring defines the area to be extracted (Fig. 5). Clamp the cell
twocleaningheads57mm(2 ⁄4in.)diameter)bycoveringwith
fourthicknessesofcleaningtissuesclampedsmoothlyinplace. intheframewithalightpressurefromthewingnuts;introduce
10 mL of distilled water with the 10-mL repeating pipet, swirl
With the repeating pipet expel exactly 0.021 mL of distilled
water at the center of the tissue on the first cleaning head. the water in the cell momentarily and let stand for 3 min, give
the solution in the cell another swirl and pour out into a clean
9.3.2 Immediately place the cleaning head with tissue side
againstthesoiledspecimen,engagethespindle,andoperatefor and dry 100 mL beaker; transfer a portion of the extract to a
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C756 − 87 (2011)
Metric Equivalents
AB C
1 1
in. 10 ⁄2 ⁄4
(mm.) (254) (13) (6.4)
FIG. 4 Spindle for Polisher
FIG. 5 Equipment Used in Soiling and Cleaning Specimens
clean, dry cuvette and place the cuvette in a rack until the other 9.5 MeasurementofFluorescence—Operate the fluorometer
five extracts are ready for measurement in the fluorometer. according to the manufacturer’s instructions. Measure and
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C756 − 87 (2011)
record the fluorescence of a distilled water blank. Measure and 10. Calculation of a Cleanability Index
record in turn the fluorescence of the solutions extracted from
10.1 Subtract the measured fluorescence value for the dis-
the specimens.
tilled water blank from the measured fluorescence value for
each of the six test surfaces and the six standard reference
NOTE 2—If concentrated solutions give off-scale readings, a 0.9
surfaces. This will result in corrected fluorescence values for
neutral-density filter should be inserted between the fluorescing solution
the six test surfaces and for the six standard reference surfaces.
and the photomultiplier. This filter transmits only 12.5 % of the light
emitted by the solution, reducing the fluroescence readings and bringing
10.2 Calculate the average of the corrected fluorescence
them on scale. Redetermine the blank reading with the filter in place and
values for the six test surfaces and for the six standard
multiply the reduced reading by 8.0 which is 1 divided by the 12.5 %
reference surfaces.
transmission of the neutral density filter.
10.3 Calculate the coefficient of variation of the corrected
9.6 Standard Reference Surface—Apply the test procedure
fluorescence values for the six test surfaces and for the six
outlined in 7.1 through 7.5 to the Standard Reference Surfaces
standard reference surfaces.
at least once during each testing day to obtain the average
10.4 Repeat the cleanability determinations on all six speci-
fluorescence of solutions extracted from these specimens.
mens (either the test specimens or the six standard reference
specimens) if the coefficient of variation is greater than 20 %.
9.7 Preferred Methods of Equipment Cleaning:
10.5 The cleanability index is calculated as follows:
9.7.1 The successful use of the fluorimetric analytical tech-
niques employed in this procedure demands that a scrupulous
CI 5 Ft/Fr (1)
level of cleanliness be maintained throughout. An oily thumb-
where:
print on the glass cuvette containing the solution to be
CI = the cleanability index of the surface being tested,
measured may be more fluorescent than the unknown.
Ft = the average co
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